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Structural study of ethyl 3‐arylcarbamoyl‐2,3‐diazabicyclo[2.2.1]hept‐5‐ene‐2‐carboxylates: conformation and transmission of substituent effects across the diazabicycloheptene ring
Author(s) -
Perjéssy A.,
Meyer P.,
Rudorf W.D.,
Loos D.,
Kolehmainen E.,
Laihia K.,
Nissinen M.,
Koivisto J.,
Kauppinen R.
Publication year - 2001
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.436
Subject(s) - chemistry , substituent , ene reaction , nitrogen inversion , ring (chemistry) , stereochemistry , cycloaddition , crystallography , computational chemistry , nitrogen , organic chemistry , catalysis
Nine new ethyl 3‐arylcarbamoyl‐2,3‐diazabicyclo[2.2.1]hept‐5‐ene‐2‐carboxylates were prepared by a [4 + 2] cycloaddition and their FTIR, 1 H, 13 C and 15 N NMR spectra were measured and assigned. Single crystals were grown for five compounds and their X‐ray data were obtained. The electronic structure and the conformations were calculated by the semi‐empirical AM1 method. Using correlations between the spectral, empirical and theoretical structural data, the transmission of substituent effects and the preferential conformation connected with the consecutive double nitrogen inversion and regarding the mutual orientation of NH and CO bonds were investigated. The results are compared with those for a previously reported series of analogous ethyl 2‐arylcarbamoyl‐4,5‐dimethyl‐1,2,3,6‐tetrahydropyridazine‐1‐carboxylates. Copyright © 2001 John Wiley & Sons, Ltd.